The present invention relates to the process for preparing carboxylic acid salts starting from organic halides. More particularly, this invention relates to the single phase carbonylation of organic halides by the reaction of such halides with carbon monoxide catalyzed by complexes of palladium and utilized with an excess of phosphine in the reaction.
The compounds thus obtained have important industrial applications. Their acids may be used in various technological fields such as, for instance, in the preparation of cosmetic products (perfumes from benzoic and phenylacetic acids, etc.), products from agriculture (3,5-dichloro-N-(1,1-dimethyl)-2-propenyl benzamide; Cidial etc.), of dye stuffs and pigments (naphthoic acid), of plasticizers (terephthalic acid), etc.
It is known to carbonylate halohydrocarbons such as benzyl chloride by the reaction of carbon monoxide and alcohol at 100.degree. C. or below and at atmospheric pressures in the presence of an amine and a catalytic amount of a palladium catalyst to form esters. U.S. Pat. No. 3,116,306 discloses a process for preparing carboxylated organic compounds such as acids by reacting
(1) an organic compound represented by the general formula R.sub.n Z in which R is an organic compound having at least one aliphatic radial or cycloaliphatic radial, Z is SO.sub.4, X, X.sub.2 or R'SO.sub.3, X being a halogen and R' is alkyl, alkenyl, cycloaklyl, aryl or arylalkyl where N is 1, Z is X, X.sub.2 or R'SO.sub.3 and where N is 2, Z is SO.sub.4, the Z substituent being attached to an aliphatic or a cycloaliphatic primary or secondary carbon atom; PA1 (2) carbon monoxide; PA1 (3) a salt of a metal hydrocarbonyl of the group consisting of cobalt hydrotetracarbonyl and iron dihydrotetracarbonyl; and
(4) a material of the group consisting of water, alcohols, phenols, mercaptans, ammonia, hydrazine, primary organo-nitrogen bases and secondary organo-nitrogen bases.
U.S. Pat. No. 4,034,004 discloses a process for the preparation of carboxylic acids from organic halides. The disclosed process comprises the reaction of aromatic or aliphatic organic halides with carbon monoxide utilizing a phosphinic palladium complex catalyst in the presence of a quaternary alkyl ammonium salt wherein the process is conducted in a double liquid phase consisting essentially of the organic halide and catalytic palladium complex and an aqueous inorganic alkaline solution containing the quaternary alkyl ammonium salt.
Unlike the present single phase system disclosed in the instant application, the above reference discloses a two-phase system. In addition, the reference teaches the use of a solvent that is immiscible in H.sub.2 O.